The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

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An airtight fabric suit with flexible joints that
enables a person to live and work in the harsh,
airless environment of space (see space survival). A
spacesuit maintains a pressure around the body to
keep body fluids from boiling away, a comfortable
temperature, and a supply of oxygen. The modern
spacesuit is a development of the pressure suits worn
by early high-altitude pilots.
Pre-Apollo Wardrobe
Pressure suits were suggested by the British physiologist
J. B. S. Haldane as long ago as 1920, but they were
first built in 1933 by the B. F. Goodrich company for
the pioneer American aviator Wiley Post. By wearing
a pressure suit, Post was able to fly his celebrated
supercharged Lockheed Vega monoplane, Winnie
Mae, in December 1934 to an altitude of 14,600 m. By
the end of the decade, other nations had flown generally
similar suits, and, in 1938, the Italian pilot Mario
Pezzi reached an altitude of 17,080 m—a record that
still stands for a piston-engine airplane.
The spacesuit worn by the Mercury astronauts was
a modified version of the U.S. Navy high-altitude jet
pressure suit. It had an inner layer of Neoprene-coated
nylon fabric and an outer layer of aluminized nylon
that gave it a distinctive silvery appearance. Simple
fabric break lines sewn in to allow bending at the
elbow and knee when the suit was pressurized tended
not to work very well: as an arm or leg was bent, the
suit joints folded in on themselves, reducing the suit’s
internal volume and increasing its pressure. Fortunately,
the Mercury suits were worn “soft” or unpressurized
and served only in case the spacecraft cabin
lost pressure. Individually tailored to each astronaut,
they needed, in Walter Schirra’s words, “more alterations
than a bridal gown.”
For the Gemini missions, which would involve
astronauts intentionally depressurizing their cabins
and going on spacewalks, mobility was a crucial issue.
To address this, designers came up with a suit that
consisted of a gas-tight, man-shaped pressure bladder,
made of Neoprene-coated nylon, covered by a layer
of fishnetlike fabric called Link-net, which was woven
from Dacron and Teflon cords. This net layer served
as a structural shell to prevent the bladder from bal-
spacesuit
looning when pressurized. Next came a layer of felt,
seven layers of insulation to protect against temperature
extremes, and an outer nylon cover. The suit was
pressurized at one-quarter atmospheric pressure, and
oxygen was piped in from the spacecraft’s life-support
system through an umbilical cord.
Suited for the Moon
The Apollo missions posed spacesuit designers with a
new set of problems. Not only did the Moon explorers’
outfits need to protect against sharp rocks and the
heat of the lunar day, but they also had to be flexible
enough to let astronauts stoop and bend to collect
lunar samples, set up scientific equipment, and drive
the lunar rover. Apollo spacesuit mobility was
improved over earlier designs by using bellowslike
molded rubber joints at the shoulders, elbows, hips,
and knees. Further changes to the suit waist for
Apollo 15 to 17 added flexibility, making it easier for
crewmen to sit on the lunar rover. A Portable Life
Support System (PLSS) backpack, connected to the
suit by umbilicals at the waist, provided oxygen, suit
pressurization, temperature and humidity control,
and power for communications gear for moonwalks
lasting up to 7 hours. A separate 30-minute emergency
supply was carried in a small pack above the
main PLSS.
The Gemini missions had taught that strenuous
activity in space could soon cause an astronaut to
overheat. So, from the skin out, the Apollo A7LB
spacesuit began with a liquid-cooling garment, similar
to a pair of long johns with a network of tubing sewn
onto the fabric. Cool water, circulating through the
tubing, transferred metabolic heat from the astronaut’s
body to the backpack and thence to space. Next
came a comfort and donning improvement layer of
lightweight nylon, followed by a pressure bladder, a
nylon restraint layer to prevent ballooning, a lightweight
thermal super-insulation of alternating layers
of thin Kapton and glass-fiber cloth, several layers of
Mylar and spacer material, and, finally, protective
outer layers of Teflon-coated glass-fiber Beta cloth.
The fishbowl-like helmet was formed from highstrength
polycarbonate and attached to the spacesuit
by a pressure-sealing neck ring. Unlike Mercury and